Re: [DML] Re: Engine sources

["B Benson" <delornut@xxxx>]

> OK. I've tried to guess and have worked in the >auto repair
business
> over 20 years, but I have yet to figure out what you >mean by "odd fired"
> engine. Could you explain that one for me?
> Don VIN 6860

Engine manufacturers commonly design engines with two opposing cylinders
sharing one crankshaft journal. This is cheaper than making a crankshaft
with a separate journal for each cylinder and is entirely adequate for
everyday driving. When the cylinders are arranged in a 90 degree
configuration with 6 opposing cylinders like the DeLorean's, the
mathematics work out to one opposing cylinder creating more crankshaft
rotation than the other. One turns the crank 120 degrees and the other 60
degrees. Ignition and valve timing must be tuned to this configuration so
there is an odd firing sequence between opposing cylinders. 
Adding 2 more cylinders to make a 90 degree V-8 makes the math work out even
firing with two cylinders sharing a common journal. Newer designed V-6's are
done with the cylinders opposed at 60 degrees which makes the math work out
even. It's my understanding the engine in the DeLorean was originally
designed as a V-8 which in a 90 degree configuration works out to even
firing. When 2 cylinders were lopped off it became odd firing.

Bruce Benson